In 1941 a Swiss engineer named George de Mestral came home from a walk and found burdock burrs stuck to his trousers and all through his dog’s coat. He put one under a microscope and saw it was covered in tiny hooks that caught on anything with a loop. Fourteen years later he patented a fastener built on the same plan, and named it from the French for velvet and hook: Velcro. What I keep coming back to is what the burr was for. It isn’t trying to hold on. It’s a seed trying to be carried off and dropped somewhere new, and a hook that never let go would be a failure: a seed riding a fox for the rest of its life, never touching soil. So the thing he copied was a grip designed to give up at the right moment, and that is exactly what we use it for. Nobody closes a shoe with Velcro because it holds best. They use it because it lets go.